Distillation of lubricating stock



April 23, 1929. A. G. PETERKIN, JR., Efr AL DISTILLATION OF LUBRICATING STOCK Filed April 14. 1926 Q //LVENTORS Patented Apr. 23, 1929.

UNITED STATES 1,710,240 PATENT OFFICE.

ALBERT G. PETERK-IN, JR., OF BRYN ,MAWR, WILLIAM F. STROUI, UJ'R.,A OF CYNWYI), .AND RICHARD B. CHILLAS, JR., OF PHILADELPHIA, PENNSYLYANIA, ASSIGNORS TO THE ATLANTIC REFINING COMPANY, OF PHILADELPHIA, PENNSYLVANIA, vA COB'- PORATION 0F PENN'SYLVANIA.

DISTILLATION- ,OF LUBRICATING STOCK.

ture in excess of itsusual or normal crack' ing temperature to vaporize a substantial :portion of the mixture, the vapors being kept in contact with the liquid oil until the maximum temperature is reached, and the vapors are then separated from the liquid, and the liquid `oil is immediately cooled to aatemperature below the-cracking temperature, or to a temperature which with attendant conditions Will prevent cracking.

Furtherin accordance with our invention, apetroleum product containing substantial quantities of lubricating stock, such as arafvses fine distillates or the like containing su stantial'quanties of high viscosity lubricating stock, is mixed with lower boiling oil as naphthaand subjected to, treatment of the character above referred to. This process yields, without substantial cracking, a liquid oil residuum or bottoms constituting a sat-A isfalctory lubricating stock or heavy cylinder stoc Further, a distillate containing substantial quantities of lubricating stock may be procured from distillation of crude petroleum or suitable petroleum product in a method of the character described in our co-pending application Serial No. 34,750, filed June 4, 1925, and then re-run 1n dilution with naphtha or the like, in accordance with this process, `to

.yield a heavyA lubricating or cylinder stock as residuum or bottoms.

Our invention resides insamethod of the character hereinafter described and laimed.

This application is in part a continuation of our prior application, Serial No, 34,750, filed June 4, 1925, which covers -a general method of distillation of oils. This general method is not` directly applicable to the distillation o certain crude petroleums or petroleum products which are deficient ,in low boiling materials and which cannot, therefore, be distilled to a desirable percentage bottoms without running to such high temperature that cracking occurs even by the use Application filed April 14, 1926. Serial No. 101,857.

of the process described in said prior application. In accordance with the present invention this deficiency of low boiling compounds is overcome by the addition of a lower boiling oil, which has the effects of lowering the temperature towhich the oil must be heated in order to produce the desired bottoms-and of ensuring in the still or heating structure, the desired degree of turbulence and velocity by vaporization ofthe added lower boiling oil. This lower boiling oil may be a distillate, lasfor"example, naphtha, or may be .an oil of the general character of the oil to be distilled, but richer inilo'w boiling' compounds, distilling, for example, below 500"l F. We liavefound thatwhen distilling oils showing less than 30% distillate below 500 F. by the distillation method D86-25T, A. S.,T. M. Tentative Standards, 1925, page 325, it is frequently advisable to adjust the content of these low boiling materials by the addition of a naphtha or other lower boiling oil, so as to bring the amount distilling below 500o F. to at least 30%.

The type of oil to be treated generally benefiting by such admixture is such an oil which by the vacuum assay distillation test, as described inA Industrial and Engineering Chemistry, 1925, vol. 17, No. 12, page 1248, will show under an absolute pressure of 10 m. m. (Hg) at least 20% residuum at 650 F.

For an understanding of our precess and for an illustration of an apparatus utilizable for practice of the same, refernce is made to the accompanying drawing, in which:

H is an oil heater of any suitable type, comprising tubes T disposed in the tube chamber` A, whoselower end communicates with a stack or Hue o; and into whoseupper end are discharged from the combustion chamber B the hot ases and products of combustion resulting rom the burning of any suitable fuel, as oil orl gas, delivered to the burner br The petroleum or petroleum product dilut-ed with ,lower'boiling oil as naphtha or equivalent, is delivered through the pipe. c to the pump P which delivers it at suitable pressure .to the inlet of the tube system T through which it rises counter current to the descending hot gases and is discharged` through the pipe d into the chamber C, which, in the example illustrated, is a fractionating column or tower, having, for example, the

CTI

ing a suitable-paraffne distillateL fraction and bottoms suitable only for fuel. This cut, containing substantial quantities of lubricating stock andsubstantially no components boiling below 500-F., may 1n accordance Gravity 21.1 A. P. I. Viscosity 210 F. (Saybolt Universal) 150 Flash 540 F. Fire 635 F.

In the commonly used methods the parat'- ine distillate is the only lubricating oil traction obtained and its viscosity is much lower than that of the lubricating oil produced by our method. i

In connection with the re-running, by our process, of a heavy overhead such as the above, containing, for example. a considerable percentage of oils with a Saybolt Universal viscosity of 100 seconds or above at 210 F., we add an amount of a naphtha fraction, boiling largely below 500 F. at atmospheric pressure, in an amount of the order of 60 of the charge.

The addition of the naphtha makes use of the fact that the presence of the low boiling constituents has the effect of lowering the boiling point of the high boiling oils. By its use distillation to a denite percentage bottoms may be accomplished at a much lower temperature than is necessary without it, and we are able 'to distill material which otherwise could not be distilled without the use of excessive quantities of steam, as it would decompose before reaching its boiling point. At the same time in the case of a pipe still, when operating in accordancewith the present process, on account of the greater proportion of vapor the linear rate of therflow through the tubes is increased,giving greater turbulence and 'shortening the time during which the oil must be maintained at a high temperature. These three factors combine to minimize cracking.

What we claim is:

1. The method of distilling a hydrocarbon oil characterized in that it leaves a residue of at least 20% when distilled to 650 F. under an absolute pressure ot l0 mm. of mercury, which comprises admixing with the oil a petroleum distillate substantially all of which will distil below 500 F. under atmospheric pressure, rapidly heating the mixture to atemperature in excess of that at which substantial cracking of the oil would occur if the mixture were permitted to remain at such temperature for a prolonged period of time,

immediately thereafter separating from that portion of the mixture which remains liquid the vapors which form asA a result of the heating aforesaid` then before substantial cracking occurs, passing the liquid so separated into a zone substantially devoid ot' the separated vapors, and cooling it while in said zone to prevent cracking.

2. The method of distilling a hydrocarbon oil characterized in that it leaves a residue of at least 20% when distilled to 650 F. under an absolute pressure ot' 10 mm. ot' mercury, which comprises admixing with the oil a petroleum distillate substantially all of which will distil below 500 F. under atmospheric S0 pressure, rapidly heating the mixture tb a temperature in excess ot 750 F., immediately thereafter separating from that portion of the mixture which remains liquid the vapors which form as a result of the heating aforesaid, then' before substantial cracking occurs passing the liquid so separated into a zone substantially devoid of the separated vapors, and bringing it while in said zone into Contact with a gaseous medium for effecting further separation of vapors and for cooling to prevent substantial cracking.

3. The method of distilling a hydrocarbon oil containing lubricating stock and characterized in that it leaves a residue of at least .95

20% when distilled to 650 F. under an absolute pressure of l0 mm. of mercury, which comprises admixing with the oil a petroleum distillate substantially all of which will distil below.500 F. under atmospheric pressure, l

rapidly heating the mixture to a temperature in excess of that at which substantial cracking of the oil would occur if the mixture were permitted to remain at such temperature for a prolonged period of time. immediately there- .after separating from that portion of the mixture which remains liquid the va ors which form as a result of the heating afliresaid, then before substantial cracking occurs passing the liquid so separated into a zone 11 substantially devoid of theseparated vapors, and cooling it while in said zone to prevent substantial cracking and to effect a residuum of lubricating stock.

4. The method of distilling a distillate of hydrocarbon oil` containing lubricating stock and characterized in that it leaves a residue of at least 20% when distilled to 650 F. under an absolute pressure of 10 mm. of mercury, which comprises admixing with the oil a petroleum distillate substantially all of'ewhich will distil below 500 F. under atmospheric pressure, rapidly heating the mixture toa temperature in excess ot that at which substantial cracking of the oil would occur if the mixture were permitted to remain at such temperature for a prolonged period of time, immediately thereafter separating from that portion ofthe mixture which remains liquid the vapors which form as a result ofthe heat- 13 ing aforesaid, then before substantial cracking occurs passing the liquid so separated into a zone substantially devoid of the separated vapors and bringing it into contact Witha gaseous cooling medium While in said zone, for ei'lecting further separation of vapors and for cooling to prevent substantial cracking,

and to effect a fesiduuin o lubricating stock.v

5. The method of distilling hydrocarbon oil characterized in that it leaves a residue of at least %-When distilled to 650 under an absolute pressure of l0 min. of mercury which comprises adrnixing with the oil a petroleum distillate in such proportions that at least of the mixture boils below 500O l?. at atmospheric pressure, rapidly heating the mixture to a temperature in excess of that at which substantial cracking of the oil would occur if the mixture were permitted to remain at such temperature for a prolonged period of time, immediately thereafter separadtingl :trom that portiono the mixture which remains liquid the vapors which torni as `a result of the heating aforesaid, then before substantial cracking occurs passing the liquid so separated into a Zone substantially devoid of the separated vapors, and cooling it While in said zone to prevent cracking= 6. The method of distilling a hydrocarbon oil characterized in that it leaves a residue of atleast 20% When distilled to 650o F. under an absolute pressure of 10 mm. of mercury,

which comprises admixing with the oil a pe' troleum distillate substantially all of which distilsbeloiv 500 F. under atmospheric pressure, rapidly heating the mixtiuelto a teni perature in excess of that at which substantial cracking of the oil would occur if the mixture Were permitted to remain at such telnperature for a prolonged period of time, iinmediately thereafter separating from that portion of the mixture which remains liquid the vapors which torni as a result of the heating aforesaid7 then bejiore substantial cracking occurs passing the liquid so separated into a zone substantially devoid of the separated vapors, cooling it While in said zone to prevent cracking, fractionating the separated vapors by passing them countercurrent to astream ot reflux liquid oil, and drawing ed a portion of said reLiuX oil from contact with the vapor at a point in its course of travelo G. PETEEKN, die l/VMJLAM F. STRUD, Jn.'

RECHARB B. CALLAS, Jn., 

